1. Field of the Invention
The present invention relates to optical subassemblies, and particularly to a receptacle-type optical subassembly having a replaceable sleeve portion.
2. Description of the Related Art
Optical subassemblies are utilized in optoelectronic transceiver modules and coupled to optical connectors for providing bi-directional transmission of data between an electrical interface and an optical data link. Generally, an optical subassembly includes a housing, a lens and an optical element. The housing includes a cavity for accommodating the optical element, and a fixing hole for receiving a ferrule of the optical connector. Popular Face Contact/Subscriber Connector (FC/SC) style optical connectors and small form factor (SFF) optical connectors utilize ferrules having diameters of 2.5 mm and 1.25 mm respectively. Furthermore, the engaging structures of such connectors that attach the ferrule in the fixing hole of the optical subassembly also vary. Therefore, it is frequently problematic when the optical connector for a given optical subassembly needs to be changed.
U.S. Pat. No. 5,692,083 discloses an integrally molded in-line optical piece. The optical piece has an optical sleeve for receiving an optical connector, an integrally molded lens, and a cavity for reception of an optical header. The optical piece is integrally molded. Therefore, when the optical connector in the optoelectronic transceiver module is changed, the entire optical piece must also be changed. This unduly inflates costs.
U.S. Pat. No. 5,189,716 discloses a photo-semiconductor module for being optically coupled to an optical connector. The module comprises a holder assembly, a photo-semiconductor, and a lens. Each such component is individually made, and the components are then joined together by soldering or press-fitting. The components must be assembled with great accuracy. Production costs are correspondingly high.
In view of the above, there is a need for an improved optical subassembly which overcomes the abovementioned problems.
Therefore, an object of the present invention is to provide an optical subassembly having a holding member which is easily replaceable.
Another object of the present invention is to provide an optical subassembly which can be easily and quickly assembled.
A further object of the present invention is to provide an optical subassembly which is inexpensive.
To achieve the above objects, an optical subassembly includes an optical sleeve, a lens holder having a cylindrical cavity defined therein, and an optical element received in the cavity. A stepped fixing hole is longitudinally defined through the optical sleeve, for receiving an optical connector. The lens holder includes the cavity, a lens member, and a cylindrical protuberance extending from a top surface of the lens holder. The protuberance is coupled into the fixing hole to ensure precise alignment of the optical connector, an optical axis of the lens member and the optical element. The optical sleeve is readily detachable from the lens holder. Therefore, when the optical connector needs to be changed to another kind of optical connector, the original optical sleeve can be replaced with a new suitable optical sleeve. The same lens holder can continue to be used.
Other objects, advantages and novel features of the present invention will be drawn from the following detailed description of a preferred embodiment of the present invention with attached drawings, in which: